The Sūfīs distinguish three organs of spiritual communication: the heart (_qalb_), which knows God; the spirit (_rūh_), which loves Him; and the inmost ground of the soul (_sirr_), which contemplates Him. It would take us into deep waters if we were to embark upon a discussion of these terms and their relation to each other. A few words concerning the first of the three will suffice. The _qalb_, though connected in some mysterious way with the physical heart, is not a thing of flesh and blood. Unlike the English ‘heart,’ its nature is rather intellectual than emotional, but whereas the intellect cannot gain real knowledge of God, the _qalb_ is capable of knowing the essences of all things, and when illumined by faith and knowledge reflects the whole content of the divine mind; hence the Prophet said, “My earth and My heaven contain Me not, but the heart of My faithful servant containeth Me.” This revelation, however, is a comparatively rare experience. Normally, the heart is ‘veiled,’ blackened by sin, tarnished by sensual impressions and images, pulled to and fro between reason and passion: a battlefield on which the armies of God and the Devil contend for victory. Through one gate, the heart receives immediate knowledge of God; through another, it lets in the illusions of sense. “Here a world and there a world,” says Jalāluddīn Rūmī. “I am seated on the threshold.” Therefore man is potentially lower than the brutes and higher than the angels. “Angel and brute man’s wondrous leaven compose; To these inclining, less than these he grows, But if he means the angel, more than those.” Less than the brutes, because they lack the knowledge that would enable them to rise; more than the angels, because they are not subject to passion and so cannot fall. How shall a man know God? Not by the senses, for He is immaterial; nor by the intellect, for He is unthinkable. Logic never gets beyond the finite; philosophy sees double; book-learning fosters self-conceit and obscures the idea of the Truth with clouds of empty words. Jalāluddīn Rūmī, addressing the scholastic theologian, asks scornfully: “Do you know a name without a thing answering to it? Have you ever plucked a rose from R, O, S, E? You name His name; go, seek the reality named by it! Look for the moon in the sky, not in the water! If you desire to rise above mere names and letters, Make yourself free from self at one stroke. Become pure from all attributes of self, That you may see your own bright essence, Yea, see in your own heart the knowledge of the Prophet, Without book, without tutor, without preceptor.” This knowledge comes by illumination, revelation, inspiration.